Cryosurgery device

ABSTRACT

A cryosurgery device includes an aerosol container holding a liquid refrigerant and having a valve and a stem extending out therefrom; an actuator seated on the stem and including an outlet tube for receiving released refrigerant from the container; a hub mounted on the container and including slots therein; and a base having a central opening for receiving the hub, the base including aligning projections that enter the slots in the hub to engage and apply pressure to the actuator to cause the actuator to depress the stem and release refrigerant into the base. The container may further contain an applicator tube mounted to the hub in fluid communication with the outlet tube with a porous tip mounted to a distal end of the applicator tube for receiving the refrigerant and, being chilled thereby, applied to a skin lesion to be treated.

This application is a continuation of U.S. Ser. No. 11/222,353, filedSep. 8, 2005, now U.S. Pat. No. 7,604,632, which was acontinuation-in-part application of U.S. application Ser. No.10/643,301, filed Aug. 19, 2003, now abandoned, the contents of whichare hereby incorporated in their entirety into the presentspecification.

INTRODUCTION TO THE INVENTION

The present invention relates generally to a cryosurgery device forcryogenically treating skin lesions and, more particularly, is directedto a cryosurgery device for applying a cryogenic refrigerant from apressurized container to a porous-tip applicator which contacts the areaof the skin lesion to freeze the skin lesion.

Historically, physicians have used liquid nitrogen applications toremove lesions from the skin. This has been very effective, but suffersfrom the disadvantage of requiring specialized equipment to condensenitrogen, the need for specialized storage devices, and the inherenthazards of handling and dispensing a material having a boiling point of−196° C. A certain amount of skill is required during treatment, so thatexcessive tissue injury is not obtained.

More recently, methods were developed to treat skin lesionscryogenically by employing a liquid refrigerant contained in apressurized container. In such methods, an effective amount of thecryogenic agent from the pressurized container is supplied into a hollowsupply tube, having a cotton or plastic foam applicator located at thedistal end of the tube, so that the cryogenic material accumulates inthe applicator. The skin surface of the lesion is then contacted withthe applicator having the accumulated cryogenic agent for a period oftime sufficient to permit the cryogenic agent to reduce the temperatureof the skin lesion tissue to temperatures that freeze the skin, suchthat permanent, irreversible rupture of cellular membranes of cells ofthe skin lesion occurs while the cryogenic agent is evaporating.Subsequently, the applicator is removed from the skin surface after aperiod of time that is generally about 20 to about 60 seconds, dependingon the boiling point of the refrigerant and the depth of tissue thatwill be frozen, and the frozen skin tissue of the skin lesion is thenpermitted to slowly thaw. During the next several weeks, the tissue thatwas frozen dislodges from the surrounding skin.

Examples of devices for applying a cryogenic agent to a skin lesion aredisclosed in U.S. Pat. No. 4,865,028 (Swart); U.S. Pat. No. 5,516,505(McDow); U.S. Pat. No. 5,200,170 (McDow); U.S. Pat. No. 5,330,745(McDow); U.S. Pat. No. 5,738,682 (Jensma); U.S. Pat. No. 6,092,527(Jensma); U.S. Pat. No. 6,296,410 (Ruizendaal); and U.S. Pat. No.6,387,090 (Jensma).

A problem with such devices is the manner in which the cryogenic agentis moved from the container to the applicator. It is important thatthere be little loss in the cryogenic material during such transfer and,therefore, that the cryogenic material travels the most effective andshortest path in order to provide the greatest effectiveness in treatingthe skin lesion. Further, it is necessary to prevent accidental releaseof the cryogenic material to conserve the cryogenic agent, and toprevent injury to a user of the device.

SUMMARY OF THE INVENTION

Accordingly, it is a feature of the present invention to provide acryosurgery device for freezing a skin lesion that overcomes theaforementioned problems.

It is another feature of the present invention to provide a cryosurgerydevice for freezing a skin lesion that provides an accurate andcontrolled supply of the cryogenic refrigerant.

It is still another feature of the present invention to provide acryosurgery device for freezing a skin lesion that reduces waste ofcryogenic agent.

It is yet another feature of the present invention to provide acryosurgery device for freezing a skin lesion that substantially reducespotentially dangerous conditions from occurring during an uncontrolledescape of the cryogenic agent.

It is a further feature of the present invention to provide acryosurgery device for freezing a skin lesion in which the cryogenicmaterial travels the most effective and shortest path to the applicatortip.

It is a still further feature of the present invention to provide acryosurgery device for freezing a skin lesion that is economical tomanufacture and easy to use by consumers.

In accordance with an embodiment of the present invention, a cryosurgerydevice for use with an aerosol container of the type having a valve anda stem extending outward from the valve and the container, the containerholding a propellant refrigerant therein, includes an actuator adaptedto seat on a stem of the valve in order to depress the stem and releaserefrigerant from the container. The actuator includes an outlet tube forreceiving the released refrigerant from the container. A hub is adaptedto mount on the container, the hub including at least one openingtherein and a first aligning arrangement. An applicator tube is mountedto the hub in fluid communication with the outlet tube of the actuator,and a porous tip is mounted to a distal end of the applicator tube forreceiving the refrigerant. A base has a central opening for receivingthe hub and applicator tube therein. The base includes at least one keyand a second aligning arrangement for cooperating with the firstaligning arrangement such that the at least one key enters the at leastone opening in the hub to engage and apply pressure to the actuator tocause the actuator to depress the valve stem and release therefrigerant.

The actuator includes an inlet tube connected with the main body andadapted to receive the stem of the valve therein, and a main body thatconnects together the inlet tube and the outlet tube in fluidcommunication with each other. The main body includes an arrangement forlimiting insertion of the stem into the inlet tube, and an actuatingsurface against which at least one key engages, such that application ofthe pressure to the actuating surface causes the actuator to move suchthat the shoulder engages and depresses the stem to release therefrigerant. The main body includes a generally cylindrical side wall, abottom wall which closes the side wall and which includes an opening,with the inlet tube and outlet tube being connected to opposite sides ofthe bottom wall in surrounding relation to the opening therein, and aledge connected with an upper edge of the side wall, the ledge definingthe actuating surface. The main body further includes reinforcing ribson an outer surface of the side wall and connected with the ledge.

The applicator tube includes an enlarged diameter section at a distalend thereof for receiving the porous tip therein. The hub includes asecuring arrangement for releasably securing the applicator tubethereto. Specifically, the applicator tube includes at least oneprojection extending outwardly from a lower end thereof, and thesecuring arrangement includes a threaded securing arrangement forthreadedly receiving the at least one projection of the applicator tubein a releasable securing manner. The threaded securing arrangementincludes an annular boss extending from an upper surface of the hub, atube coaxially positioned within the annular boss and connected with theannular boss at a lower end thereof, and at least one helical thread onan inner surface of the annular boss for receiving the at least oneprojection in a threaded releasable securing manner. The tube of the hubis in axial alignment with the applicator tube and the outlet tube ofthe actuator. The hub includes a cylindrical side wall, and a top wallthat closes an upper end of the cylindrical side wall, the top wallhaving an opening therein and the annular boss extends from an undersideof the top wall as the upper surface of the hub in surrounding relationto the opening therein. Further, the at least one opening is in the topwall. In one embodiment, the applicator tube further includes aplurality of grooves through which the refrigerant flows.

The hub also includes a securing arrangement at a lower end of thecylindrical side wall adapted to be snap-fit secured over an upperannular lip of the container.

The first aligning arrangement includes at least one aligning rib on thecylindrical side wall, and the second aligning arrangement includes atleast one recess for receiving the at least one aligning rib toangularly align the hub with the base. The opening in the base is closedby a lower wall at a lower end thereof.

The base includes at least one inwardly extending projection, eachhaving an upper surface on which one the key is mounted, and each theupper surface defining a limit as to an extent to which the hub can beinserted into the base. For example, there can be three projections andkeys of the base and three openings of the hub.

In accordance with another embodiment of the present invention, acryosurgery device includes a container for holding a propellantrefrigerant, the container including a valve and a stem extending outfrom the valve and the container; an actuator seated on the stem of thevalve in order to depress the stem and release the refrigerant from thecontainer, the actuator including an outlet tube for receiving thereleased refrigerant from the container; a hub mounted on the container,the hub including at least one opening therein and a first aligningarrangement; an applicator tube mounted to the hub in fluidcommunication with the outlet tube of the actuator; a porous tip mountedto a distal end of the applicator tube to be contacted by therefrigerant; and a base having a central opening for receiving the huband applicator tube therein, the base including at least one key and asecond aligning arrangement for cooperating with the first aligningarrangement such that the at least one key enters the at least oneopening in the hub to engage and apply pressure to the actuator to causethe actuator to depress the stem and release the refrigerant.

A cryosurgery device can be used to treat a skin lesion, by: mounting anapplicator tube and porous tip assembly to the hub, positioning thedevice over the base such that the base is located below the containerand the porous tip extends downwardly into a central opening of thebase; applying a force to the container, the base, or both, such thatthe keys enter corresponding openings in the hub to apply pressure tothe actuator and cause refrigerant to be released into the applicatortube; discontinuing the force after a period of time sufficient for theliquid refrigerant to chill the porous tip to a therapeuticallyeffective temperature; removing the base; and, without removing theapplicator tube and porous tip from the hub, promptly placing the poroustip in contact with a lesion to cause freezing of the lesion.

Those of ordinary skill in the art will find alternative ways foroperating the cryogenic device of the invention based on the descriptionof the device in this application. Such methods are contemplated to bewithin the scope of the invention. For example, the cryogenic device canbe operated in a way that does not require the use of an applicator tubemounted to the hub. In one embodiment of such a method, the cryogenicdevice is operated the same as described previously, but without theapplicator tube mounted to the hub, the liquid refrigerant is nowdispersed directly into the base where it collects in a pool. A separateapplicator that will withstand the temperatures of the liquidrefrigerant, for example a metal or polymer rod, with or without aporous tip, can then be immersed in the refrigerant and chilled totherapeutically effective temperature and then applied to a lesion tocause freezing of the lesion.

The above and other aspects, features, and advantages of the inventionwill become readily apparent from the following detailed descriptionthereof, which is to be read in connection with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a cryosurgery device accordingto the present invention.

FIG. 2 is a cross-sectional view of a portion of the cryosurgery deviceof FIG. 1, taken along line 2-2 thereof.

FIG. 3 is a perspective view of the actuation cup.

FIG. 4 is a top plan view of the actuation cup.

FIG. 5 is an elevational view of the actuation cup.

FIG. 6 is a cross-sectional view of the actuation cup, taken along line6-6 of FIG. 4.

FIG. 7 is a cross-sectional view of the actuation cup, taken along line7-7 of FIG. 5.

FIG. 8 is a cross-sectional view of the actuation cup, taken along line8-8 of FIG. 7.

FIG. 9 is a perspective view of the hub.

FIG. 10 is a top plan view of the hub.

FIG. 11 is a cross-sectional view of the hub, taken along line 11-11 ofFIG. 10.

FIG. 12 is a cross-sectional view of the hub, taken along line 12-12 ofFIG. 11.

FIG. 13 is a cross-sectional view of the hub, taken along line 13-13 ofFIG. 11.

FIG. 14 is a cross-sectional view of the hub, taken along line 14-14 ofFIG. 11.

FIG. 15 is a perspective view of the applicator tube.

FIG. 16 is a top plan view of the applicator tube.

FIG. 17 is a bottom plan view of the applicator tube.

FIG. 18 is a cross-sectional view of the applicator tube, taken alongline 18-18 of FIG. 17.

FIG. 19 is a cross-sectional view of the applicator tube, taken alongline 19-19 of FIG. 18.

FIG. 20 is a cross-sectional view of the applicator tube, taken alongline 20-20 of FIG. 19.

FIG. 21 is an assembled perspective view similar to FIG. 1, showing theapplicator tube assembled with the hub which is mounted on thepropellant container.

FIG. 22 is a perspective view of the mounting base.

FIG. 23 is a top plan view of the mounting base.

FIG. 24 is a bottom plan view of the mounting base.

FIG. 25 is cross-sectional view of the mounting base, taken along line25-25 of FIG. 23.

FIG. 26 is cross-sectional view of the mounting base, taken along line26-26 of FIG. 23.

FIG. 27 is cross-sectional view of the mounting base, taken along line27-27 of FIG. 23.

DETAILED DESCRIPTION

Referring to the drawings, and initially to FIGS. 1 and 2, a cryosurgerydevice 10 according to the present invention includes a propellantcontainer 12 which holds a liquid refrigerant, an actuation cup 14positioned on the stem of propellant container 12, a hub 16 mounted overactuation cup 14 and press fit onto propellant container 12, anapplicator tube 17 secured to hub 16 and a mounting base 18 forproviding actuation to supply the refrigerant to applicator tube 17. Thedevice is adapted for use to remove various skin lesions, includingverruca (warts), keratoses, achrocordon, molluscum contagiosum, agespots, dermatofibroma, keloids, granuloma annulare, porokeratosisplantaris, angiomas, lentigo maligna, keratocanthoma, basal cell,Bowen's disease, lentigo discreta, chondrodermatitis, epithelial nevus,leokoplakia, granuloma pyogenicum, and Kaposi's sarcoma. However, forthe sake of brevity, the following description will refer only totreatment of verruca; treatments for the other conditions are similar,except that the sizes of the applicator tips and the duration of contactwith the lesions can vary.

As shown in FIGS. 1 and 2, propellant container 12 includes an annularside wall 20, a bottom wall 22 which closes the lower end of annularside wall 20, a top wall 24 which closes the upper end of annular sidewall 20. A reduced diameter neck 26 is provided centrally in top wall 24and extends upwardly therefrom. Neck 20 has a top wall 28 that partiallycloses the upper end thereof and which includes a central opening 30that is in open fluid communication with the interior of container 12for delivering a liquid refrigerant held in container 12. As is typicalin the art, aerosol containers may be formed from plated steel,aluminum, and other materials; the choice of material is notparticularly critical, resistance to corrosion from contact with thecontents and an ability to withstand the internal pressures that aregenerated being the more important considerations.

The liquid refrigerant can be any suitable liquid refrigerant for use asa cryogenic agent to reduce the temperature of wart tissue to atemperature to freeze the skin, such that permanent, irreversiblerupture of cellular membranes of cells of the skin lesion occurs whilethe cryogenic agent is evaporating. If the temperature of a wart islowered below about −20° C. for at least about twenty seconds, the warttissue will be destroyed. Many low-boiling refrigerant/aerosolpropellant materials are suitable for this purpose, includinghalogenated hydrocarbons, ethers, and hydrocarbons. For environmentalreasons, the formerly very common chlorofluorocarbon refrigerants havebeen prohibited for most uses, generally being replaced byfluorohydrocarbon compounds; for example, the commercial refrigerant1,1,1,2-Tetrafluoroethane, which has a boiling point of −26.5° C., isuseful in the present invention. The materials may be mixtures ofrefrigerant compounds to lower the container internal pressures, toachieve a desired boiling point, or for other reasons. Those skilled inthe art are aware of numerous useful refrigerant compounds and mixtures.

Examples of useful mixtures are: 82 weight percent dimethyl ether and 18weight percent propane; and 95 weight percent dimethyl ether, 2 weightpercent propane, and 3 weight percent isobutane. For purposes of thepresent invention, a very suitable liquid refrigerant is a mixture of 75weight percent dimethyl ether and 25 weight percent propane, whichproduces temperatures below about −30° C. on the surface of skin of aperson when applied using the following described device.

A conventional spring-loaded pressurized “continuous” aerosol valve 32is provided in reduced diameter neck 26 of container 12. Theconstruction details of valve 32 are well known and the specificconstruction of valve 32 does not form part of the present invention.Examples of such valves can be found throughout the patent literature,for example, in U.S. Pat. Nos. 6,039,306; 6,318,603; and many otherpatents; as well as in A. R. Gennaro, Ed., Remington: The Science andPractice of Pharmacy, 20^(th) Ed., Lippincott, Williams & Wilkins,Baltimore, Md., 2000, pages 971-972; the entire disclosures of which areincorporated herein by reference. In the embodiment shown, dip tube 34is connected with valve 32 and extends into container 12, and a shortoutlet stem 36 extends out of container 12. Although not depicted in thefigures, it will be appreciated that valve 32 further comprises a vaportap that is used to expel gases along with the liquid expelled through adip tube 34 to preferably form a mist when the valve is used in theup-right position. However, in a preferred embodiment discussedthroughout this specification, container 12 is placed in contact withbase 18 in an inverted position to release the cryogen liquid, whicheliminates the effectiveness of dip tube 34 as it extends above thelevel of liquid in container 12 as inverted. Thus, in this embodiment,dip tube 34 can be made to extend into the interior of container 12 foronly a very short distance or, alternatively, the dip tube can even beeliminated, so that liquid refrigerant will be delivered exclusivelythrough the vapor tap when container 12 is inverted.

In addition, an annular lip 38 extends upwardly from the upper outeredge of annular wall 20, and includes an annular undercut 40, thepurpose for which will become apparent from the discussion hereafter.

Referring now to FIGS. 1-8, actuation cup 14 includes a main body havinga generally annular outer wall 50 which is partially closed at its lowerend by a bottom wall 52 having a central opening 54 with a first innerdiameter. Annular outer wall 50 is open at its upper end 56, and anannular ledge 57 extends outwardly from the upper end 56 in a radialdirection, forming an upper annular actuating surface 58 thereat. Anoutlet tube 60 of the same first inner diameter extends upwardly frombottom wall 52 and is coaxial with and in fluid communication withcentral opening 54. Outlet tube 60 preferably extends to a height justabove upper annular actuating surface 58, although the present inventionis not limited thereto. An inlet tube 62 having a second inner diameterwhich is greater than the first inner diameter of outlet tube 60 extendsdownwardly from the lower surface of bottom wall 52, and is in fluidcommunication with outlet tube 60 through central opening 54. Because ofthe larger inner diameter of inlet tube 62, an inner annular shoulder 64is formed at the lower surface of bottom wall 52 in surrounding relationto central opening 54 and encased by inlet tube 62. Actuation cup 14sits on short outlet stem 36 such that short outlet stem 36 is receivedin outlet tube 60, with the upper edge of short outlet stem 36 seatingat inner annular shoulder 64.

Thus, as a result of pressure applied to upper annular actuating surface58 of actuation cup 14, inner annular shoulder 64 forces short outletstem 36 inwardly of container 12 in order to open valve 32 and releasethe refrigerant, which then travels from short outlet stem 36, throughoutlet tube 60. In order to reinforce annular outer wall 50 as a resultof such pressure without adding substantially to the material and costsof actuation cup 14, strengthening ribs 66 extend out radially from theouter surface of annular outer wall 50, in angularly spaced relationfrom each other, and are also connected to the underside of annularledge 57.

As discussed above, a hub 16 is mounted over actuation cup 14 and ispress fit onto propellant container 12. Referring now to FIGS. 1, 2 and9-14, hub 16 includes an upper annular side wall 70 having a firstdiameter, a middle annular side wall 72 of a second larger diameter, anda lower annular side wall 74 of a third largest diameter. A radiallydirected annular wall 76 connects the lower edge of upper annular sidewall 70 to the upper edge of middle annular side wall 72 to form aninner annular shoulder 78 thereat, and a radially directed annular wall80 connects the lower edge of middle annular side wall 72 to the upperedge of lower annular side wall 76 to form an inner annular shoulder 82thereat. Further, the material of upper annular side wall 70 is pushedout at three equiangularly spaced vertical locations to form threeequiangularly spaced aligning ribs 84 for alignment purposes as will beunderstood from the discussion hereafter. In like manner, sixequiangular vertical reinforcing ribs 86 extend inwardly in a radialdirection from the inner surface of middle annular side wall 72.

Hub 16 is open at the lower end of lower annular side wall 74, and hasthree equiangularly spaced snap-in beads 88 on the inner surfacethereof. As a result, hub 16 can be snap fit onto propellant container12. In such case, annular snap-in beads 88 will snap over annularundercut 40 in order to hold hub 16 on container 12.

A top wall 90 closes the upper edge of upper annular side wall 70 andincludes a central opening 92, as well as three equiangularly spaced,slightly arcuate slots 94 in surrounding relation to central opening 92.When hub 16 is snapped onto container 12, as shown best in FIG. 2, upperannular actuating surface 58 of actuator cup 14 is positioned against orvery close to the lower surface of top wall 90, with upper annularactuating surface 58 immediately below slots 94.

An annular boss 96 extends down from the lower surface of top wall 90 insurrounding relation to central opening 92 for a distance almost to thelower edge of upper annular side wall 70. The inner surface of annularboss 96 is formed with a helical screw thread 98. A hollow shaft 100having an outer diameter less than the inner diameter of annular boss96, is provided coaxially within annular boss 96 and is of substantiallythe same height as annular boss 96. The lower edges of annular boss 96and hollow shaft 100 are connected together by an annular connectingwall 102. This latter arrangement is provided to capture and holdapplicator tube 17 therein.

As discussed above, applicator tube 17 is secured to hub 16. As shown inFIGS. 15-21, applicator tube 17 has a barbell-like shape. Specifically,applicator tube 17 is formed by a unitary hollow shaft 110 of agenerally constant thickness throughout. Hollow shaft 110 includes acenter section 112 of a first diameter, an upper section 114 of adiameter which is greater than the first diameter of center section 112and a lower section 116 of a diameter which is also greater than thefirst diameter of center section 112. An annular shoulder 118 is formedat the connection of the lower end of upper section 114 with the upperend of center section 112, while a second annular shoulder 120 is formedat the connection of the upper end of lower section 116 with the lowerend of center section 112.

Two diametrically opposite projections 122 extend outwardly in theradial direction from the outer surface of lower section 116 at thelower edge thereof. The outer diameter of lower section 116 is less thanthe inner diameter of annular boss 96 while the inner diameter of lowersection 116 is greater than the outer diameter of hollow shaft 100 so asto fit therebetween. In this manner, when the lower end of lower section116 is inserted between boss 96 and hollow shaft 100, and then rotated,projections 122 engage with helical screw thread 98 to releasably lockapplicator tube 17 to hub 16, as shown best in FIG. 21.

The inner surface of upper section 114 is provided with equiangularlyspaced grooves 124 that extend vertically and in the radial direction,so as to define a plurality of equiangularly spaced vertical projections126 extending inwardly in the radial direction. The grooves 124 serve toconduct the refrigerant from outlet tube 60 through applicator tube 17into contact with cylindrical tip 128.

Cylindrical tip 128 formed from a porous material is friction fit inupper section 114 and held therein by projections 126. After contactwith refrigerant, tip 128 is used to freeze the skin. Tip 128 can bemade of any suitable material, such as a polymeric foam, a sinteredthermoplastic, a sintered metal, a glass or ceramic frit, or apolyolefin or polyester nonwoven fabric. Preferably, tip 128 is securedto applicator tube 17, for example by thermal welding, ultrasonicwelding, an adhesive, etc. In general, the void volume of the porousmaterial should be greater than about 50 percent to provide sufficientcapacity for receiving liquid refrigerant for a period of timesufficient to chill tip 128 to a therapeutically effective temperature.A maximum void volume will typically not exceed about 90 percent, andwill depend on the relative rigidity and strength of the material ofconstruction so that the tip will retain its general shape during use.

Preferably, tip 128 comprises a nonwoven material in which orientedbicomponent polyethylene/polyester fibers are thermally bonded into arod configuration, having a density about 0.2 g/cm³ and a void volumeabout 80 percent. The tip can be shaped as desired, such as cylindrical,conical pointed, truncated conical, or other shapes that provide adesired skin contact area. An advantage of nonwoven material is itsrigidity, so that the desired shape is generally maintained during use,while also providing a good degree of comfort by being somewhatdeformable while held in contact with the skin. Also, the importantproperties of nonwoven materials are not substantially changed as thetemperatures vary during use in the invention.

In a presently preferred embodiment, an applicator tube 17 is about 25mm (1 inch) in length and center section 112 has an inner diameter about5 mm (0.2 inches); the inner diameter of upper section 114, betweenopposite projections 126, is about 6 mm (0.23 inches) to enhanceretention of the porous tip. The porous tip has a diameter about 6.4 mm(0.25 inches) and a length about 12.7 mm (0.5 inches); at least abouthalf of the length of the tip will typically extend beyond the upperedge of the applicator tube. When formed from the nonwoven materialdescribed above, a tip of these dimensions will have a mass about 75 mg.

When valve 32 is opened, the liquid refrigerant flows through applicatortube 17 via grooves 124 and contacts tip 128, thereby chilling tip 128by the immediate evaporation of refrigerant. Then, chilled tip 128 canbe briefly pressed against a wart to be removed from the skin. Asrefrigerant evaporates from the tip, it may be replenished during atleast a portion of the treatment time by liquid remaining in the tube.Preferably, for hygienic reasons, the applicator tube 17 and tip 128 areused only once, and then will be discarded.

In order to contain the refrigerant while valve 32 is open to chill tip128 base 18 is provided. Specifically, as shown in FIGS. 1 and 22-27,base 18 includes a cylindrical outer shell 140 and an inner actuatingassembly 142 mounted to and within outer shell 140. Specifically, inneractuating assembly 142 includes three equiangularly spaced short arcuatewalls 144 extending vertically down within outer shell 140, with theupper edges of short arcuate walls 144 connected to the upper edge ofouter shell 140 by connecting walls 146. As a result, aligning gaps orrecesses 148 are formed between side edges of short arcuate walls 144.

Three equiangularly spaced, inwardly extending projections 150 areconnected to outer shell 140 immediately below gaps or recesses 148.Each projection 150 has a generally trapezoidal shape with the innersurface 150 a thereof being generally arcuate. Each projection 150extends down to a distance to an approximate mid-point of the length ofouter shell 140. An upstanding arcuate key 152 extends upwardly from theupper surface 150 b of each projection 150 and is positioned near innersurface 150 a, the purpose for which will become apparent from thediscussion hereafter.

The “lock and key” combination of keys 152 and slots 94 acts to preventopening of the valve unless base 18 is properly in place over hub 16.Thus, the release of refrigerant will take place into an enclosed space,and the user will be protected against a potentially injurious contactwith the refrigerant. There typically will be up to about six each ofkeys 152 and slots 94, and their shapes can vary from the particularembodiment shown, such as being round, square, rectangular, etc.Preferably there will be at least two of the keys and slots. To provideadditional security against injury from misuse, the device is designedto deliver refrigerant in liquid form only when container 12 isinverted, and the slots 94 are less accessible to a user. Excess amountsof refrigerant will be contained within the central opening of the base,which central opening is closed by bottom wall 160.

The lower edges of projections 150 are closed by an annular wall 154 ata substantial mid-point of the length of outer shell 140, with annularwall 154 defining a central opening 156 therein. A cylindrical wall 158extends down from annular wall 154 in surrounding relation to centralopening 156, and is closed at its lower end by a bottom wall 160.Trapezoidal projections 162 of a similar shape to projections 150 areformed on the outer surface of cylindrical wall 158 and are secured tothe lower surface of annular wall 154 in alignment with the spacesbetween projections 150, in order to add structural rigidity tocylindrical wall 158. The lower ends of trapezoidal projections 162 areclosed by lower walls 164.

In operation, actuator cup 14 and hub 16 are preferably pre-assembledwith propellant container 12. Then, applicator tube 17 is assembled withhub 16 by the user by inserting the lower end of lower section 116between boss 96 and hollow shaft 100, and then rotating applicator tube17, whereby projections 122 engage with helical screw thread 98 to lockapplicator tube 17 to hub 16, as shown best in FIG. 21. As discussedabove, tip 128 is preferably permanently secured to applicator tube 17.Thereafter, with base 18 positioned on a stable surface, propellantcontainer 12 is inverted and positioned within base 18. In thisposition, aligning ribs 84 are aligned with and inserted within aligningrecesses 148 in order to angularly align container 12 with base 18.Further, applicator tube 17 extends centrally therethrough, with tip 128being positioned within cylindrical wall 158. Upper surfaces 150 bdefine a limit as to the extent to which hub 16 can be inserted intobase 18.

Due to this alignment, keys 152 extend into arcuate slots 94, and uponpressure on container 12, keys 152 engage upper annular actuatingsurface 58 of actuation cup 14 to push actuation cup 14 inwards towardcontainer 12. As a result of this pressure applied to upper annularactuating surface 58 of actuation cup 14, inner annular shoulder 64forces short outlet stem 36 inwardly toward container 12 in order toopen valve 32 and release the refrigerant, which then travels from shortoutlet stem 36, through outlet tube 60 of actuator cup 14 and thenthrough applicator tube 17 via grooves 124 so as to contact and chilltip 128 to a therapeutically effective temperature. This takes only afew seconds, and frequently as little as two seconds.

Thereafter, base 18 is removed and, without removing applicator tube 17from hub 16, tip 128 with the refrigerant contained therein isimmediately applied to the wart for a period of, for example, twentyseconds, in order to freeze the wart. After about five minutes, tip 128will have sufficiently warmed so that the applicator can be safelyremoved from the device and the applicator tube/tip assembly can bediscarded.

Base 18 can be used as a storage cover for the cryogenic surgery device,if the end opposite the end containing keys 152, etc. is sized toprovide a friction fit over container 12. An important feature of thedevice is the containment within base 18 of dispensed liquid refrigerantduring the chilling procedure, so that spillage onto the user isunlikely. As a result of this design, it is also contemplated that base18 can serve as a reservoir for the liquid refrigerant dispenseddirectly from short outlet stem 36, through outlet tube 60 of actuatorcup 14, when applicator tube 17 is not attached to hub 16. In thismanner, any known applicator material, such as a metal or nonmetal rod,including polymer materials that can withstand the cryogenictemperatures, can be immersed into the pool of liquid refrigerant for aperiod of time sufficient to chill the applicator to a therapeuticallyeffective temperature, and then applied to the lesion to be frozen. Inequally preferred embodiments, the applicator can comprise the poroustip material described above for tip 128.

With the exceptions of the aerosol container and the tip, all of thedevice components typically will be molded from one or morethermoplastic materials, such as polyethylene, polypropylene, or otherpolyolefins and polyolefin copolymers, nylons, polyesters, polyacetals,and polyurethanes. The materials of construction are not critical to theinvention.

Having described a specific preferred embodiment of the invention withreference to the accompanying drawings, it will be appreciated that thepresent invention is not limited to that precise embodiment and thatvarious changes and modifications can be effected therein by one ofordinary skill in the art without departing from the scope or spirit ofthe invention as defined by the appended claims.

PARTS DESIGNATOR LIST

-   10 cryosurgery device-   12 propellant container-   14 actuation cup-   16 hub-   17 applicator tube-   18 base-   20 annular side wall-   22 bottom wall-   24 top wall-   26 reduced diameter neck-   28 top wall-   30 central opening-   32 valve-   34 dip tube-   36 short outlet stem-   38 upwardly extending annular lip-   40 annular undercut-   50 annular outer wall-   52 bottom wall-   54 central opening-   56 upper end-   57 annular ledge-   58 upper annular actuating surface-   60 outlet tube-   62 inlet tube-   64 inner annular shoulder-   66 strengthening ribs-   70 upper annular side wall-   72 middle annular side wall-   74 lower annular side wall-   76 radially directed annular wall-   78 inner annular shoulder-   80 radially directed annular wall-   82 inner annular shoulder-   84 aligning ribs-   86 reinforcing ribs-   88 snap-in beads-   90 top wall-   92 central opening-   94 arcuate slots-   96 annular boss-   98 helical screw thread-   100 hollow shaft-   102 annular connecting wall-   110 hollow shaft-   112 center section-   114 upper section-   116 lower section-   118 annular shoulder-   120 second annular shoulder-   122 projections-   124 grooves-   126 projections-   128 tip-   140 outer shell-   142 inner actuating assembly-   144 short arcuate walls-   146 connecting walls-   148 aligning gaps or recesses-   150 projections-   150 a inner surface-   150 b upper surface-   152 upstanding arcuate key-   154 annular wall-   156 central opening-   158 cylindrical wall-   160 bottom wall-   162 trapezoidal projections-   164 lower walls

1. A cryosurgery device comprising: an aerosol container for holding arefrigerant, the container including a valve and a valve stem extendingout from the valve and the container; an actuation cup comprising a mainbody having a generally annular outer wall which is partially closed atits lower end by a bottom wall, the bottom wall having an upper surfaceand a lower surface and a central opening with a first inner diameter;an actuator seated on the valve stem in order to depress the valve stemand release the refrigerant from the container, the actuator includingan outlet tube for receiving released refrigerant from the container,the outlet tube having the same first inner diameter as the actuationcup; wherein said actuator includes an inlet tube connected with themain body and adapted to receive the valve stem therein and comprising asecond inner diameter which is greater than the first inner diameter ofthe outlet tube to form a shoulder at the lower surface of the bottomwall; and said main body connecting together said inlet tube and saidoutlet tube in fluid communication with each other, the main bodyincluding an arrangement for limiting insertion of the valve stem intothe inlet tube; and an actuating surface against which at least one keyengages, such that application of said pressure to the actuating surfacecauses said actuator to move such that the shoulder engages anddepresses the valve stem to release the refrigerant; a hub mounted onthe container, the hub including at least one opening therein and afirst aligning arrangement; an applicator tube mounted to the hub influid communication with the outlet tube of the actuator; a porous tipmounted to a distal end of the applicator tube for receiving therefrigerant; and a separate base having a central opening for receivingthe hub and applicator tube therein, the base including at least one keyand a second aligning arrangement for cooperating with said firstaligning arrangement such that the at least one key can enter the atleast one opening in the hub to engage and apply pressure to theactuator to cause the actuator to depress the stem and release therefrigerant.
 2. The cryosurgery device according to claim 1, whereinsaid main body includes: a generally cylindrical side wall, a bottomwall which closes the side wall and which includes an opening, with theinlet tube and outlet tube being connected to opposite sides of thebottom wall in surrounding relation to the opening therein, and a ledgeconnected with an upper edge of the side wall, the ledge defining saidactuating surface.
 3. The cryosurgery device according to claim 1,wherein the applicator tube includes an enlarged diameter section at adistal end thereof for receiving the porous tip therein.
 4. Thecryosurgery device according to claim 1, wherein: said applicator tubeincludes at least one projection extending outwardly from a lower endthereof; and said hub includes a threaded securing arrangement forthreadedly receiving the at least one projection of the applicator tubein a releasable securing manner.
 5. The cryosurgery device according toclaim 4, wherein said threaded securing arrangement includes: an annularboss extending from an upper surface of said hub, a tube coaxiallypositioned within said annular boss and connected with said annular bossat a lower end thereof, and at least one helical thread on an innersurface of said annular boss for receiving said at least one projectionin a threaded releasable securing manner.
 6. The cryosurgery deviceaccording to claim 1, wherein: said hub includes: a cylindrical sidewall, and a top wall which closes an upper end of said cylindrical sidewall, and said at least one opening is in said top wall.
 7. Thecryosurgery device according to claim 6, wherein said container includesan upper annular lip and said hub further includes a securingarrangement at a lower end of said cylindrical side wall adapted to besnap-fit secured over the upper annular lip of the container.
 8. Thecryosurgery device according to claim 6, wherein said first aligningarrangement includes at least one aligning rib on said cylindrical sidewall, and the second aligning arrangement includes at least one recessfor receiving the at least one aligning rib to angularly align the hubwith the base.
 9. The cryosurgery device according to claim 1, whereinthe base includes at least one inwardly extending projection having anupper surface on which one said key is mounted, said upper surfacedefining a limit as to an extent to which the hub can be inserted intosaid base.
 10. The cryosurgery device according to claim 1, whereinthere are an equal number of said keys of said base and said openings insaid hub, the number being at least three.
 11. The cryosurgery deviceaccording to claim 1, wherein said porous tip comprises a nonwovenmaterial having polyolefin and polyester components.
 12. A method oftreating a skin lesion, comprising: positioning a cryosurgery devicecomprising: an aerosol container for holding a refrigerant, thecontainer including a valve and a valve stem extending out from thevalve and the container; an actuation cup comprising a main body havinga generally annular outer wall which is partially closed at its lowerend by a bottom wall, the bottom wall having an upper surface and alower surface and a central opening with a first inner diameter; anactuator seated on the valve stem in order to depress the valve stem andrelease the refrigerant from the container, the actuator including anoutlet tube for receiving released refrigerant from the container, theoutlet tube having the same first inner diameter as the actuation cup; ahub mounted on the container, the hub including at least one openingtherein and a first aligning arrangement; an applicator tube mounted tothe hub in fluid communication with the outlet tube of the actuator; aporous tip mounted to a distal end of the applicator tube for receivingthe refrigerant; and a separate base having a central opening forreceiving the hub and applicator tube therein, the base including atleast one key and a second aligning arrangement for cooperating withsaid first aligning arrangement such that the at least one key can enterthe at least one opening in the hub to engage and apply pressure to theactuator to cause the actuator to depress the stem and release therefrigerant; such that said base is below said container and said poroustip extends downwardly into said central opening of said base; applyinga force to said container, said base, or both, such that said at leastone key enters said at least one opening in the hub to apply pressure tosaid actuator and cause refrigerant to be released into said applicatortube and porous tip; discontinuing said force after said porous tip ischilled by liquid refrigerant to a therapeutically effectivetemperature; removing said base; and without removing said porous tipfrom said hub, promptly placing said chilled porous tip in contact withsaid skin lesion for a period of time sufficient to freeze said skinlesion, thereby treating said skin lesion.
 13. The method of claim 12,wherein the skin lesion comprises a verruca.
 14. The method of claim 12,wherein the skin lesion comprises an achrocordon.
 15. The method ofclaim 12, wherein the skin lesion comprises an age spot.